Non-Circular Multimode Fiber for Compact Mode Coupling
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Solution Overview
Problem
Existing optical fiber arrangements in liquid chromatography systems are bulky and suffer from transmission losses, especially in the deep UV region, due to the need for long fibers to achieve sufficient mode coupling, which also leads to instability and drift issues.
Innovation Solution
An optical fiber arrangement with a coupling inducing section arranged in a plane on a holder, featuring open bends and non-circular cross-section fibers, secured by holding pins with varying diameters and movable pins for stable fixation and efficient mode mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical fiber is arranged in loops and bends to achieve mode coupling, then the mode coupling ability is improved, but the device becomes bulky and transmission losses increase
Solution Approach 1:
The patent applies curvature to the optical fiber by introducing bends and loops in a controlled manner within a compact holder assembly. The fiber is routed through a series of curved paths that induce mode coupling while maintaining a small overall device footprint, resolving the contradiction between mode coupling ability and device size.
Solution Approach 2:
The optical fiber is nested within a holder assembly that provides structural support and defines the curved path. The fiber is contained within the holder's confined space, allowing mode coupling to occur in a compact volume rather than requiring large external loops and bends.
2Reliability
If the optical fiber length is increased to achieve sufficient mode coupling, then the mode mixing is improved, but transmission losses increase especially in the deep UV region
Solution Approach 1:
The patent changes the physical parameters of the optical fiber system by introducing bends and loops with specific radii and configurations. These geometric parameter changes induce mode coupling that improves mode mixing quality while minimizing the total fiber length required, thereby reducing transmission losses in the deep UV region.
3Loss of energy
If the bend radius is kept large to reduce transmission losses, then the transmission efficiency is improved, but the mode coupling ability is decreased
Solution Approach 1:
The patent optimizes the bend radius parameter by introducing multiple bends with carefully controlled radii. The bends are designed with radii large enough to minimize transmission losses while still being sufficient to induce the necessary mode coupling, achieving a balance between these two competing requirements.
Solution Approach 2:
The patent employs a series of continuous bends and loops rather than single sharp bends. This continuous curved path allows light to progressively couple between modes while maintaining relatively large local radii, ensuring both low transmission losses and effective mode mixing throughout the fiber length.
4Volume of stationary object
If the optical fiber arrangement is made compact, then the device size is reduced, but stability and drift issues worsen
Solution Approach 1:
The patent nests the optical fiber within a rigid holder assembly that provides mechanical stability. The holder constrains the fiber's curved path and prevents movement or drift, ensuring output stability while maintaining a compact overall device size. The nested structure protects the fiber arrangement from external disturbances.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration results in a more compact, stable, and efficient mode coupling system with minimized losses and drift, producing high-quality uniform output light with a shorter fiber length, reducing the need for extensive fiber lengths and minimizing movement-induced errors.
Implementation Method 1
arranged the optical fiber in a series of bends and loops to allow for a coupling of propagation modes that serves to provide a smooth output of light
Implementation Method 2
optical fibers are used for propagating light within the system... providing a flexible transfer of lights and a minimal loss of intensity
Implementation Method 3
a beam splitter is used to split the light into two portions, in order to provide a stable reference portion that is not transmitted to the flow cell
Implementation Method 4
Light not absorbed after passing through this cell strikes a light detector containing one or more photosensitive elements
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
Disclosed is an optical fiber arrangement for inducing coupling among propagation modes of light, said arrangement comprising a multimode optical fiber (30) having an input end (32) for receiving light and an output end (31) for emitting light, with a coupling inducing section (33) extending from said input end to said output end, and a holder (80) on which the optical fiber is arranged, wherein said multimode optical fiber has a non-circular cross section. Disclosed also is a system for measuring the absorption or determining the concentration of a substance, said system comprising at least one optical fiber arrangement.